Deliverable D 2.1 Exploring the 15-minute city concept for urban outskirts : a systematic literature review

This report summarises the findings from a conducted systematic literature review of the 15-minute city concept (15mC), its key components and its adaptation for the neighbourhoods located in the urban outskirts. This report it is part of the DREAMS project, which aims to create sustainable, accessible, and inclusive neighbourhoods in the outskirts through proximity-centred urban planning. The DREAMS project focuses on the 15-minute planning concept for neighbourhoods in the urban outskirts, we aim to delve into the key components necessary to implement 15-minute neighbourhood (15mN) principles beyond its original setting: the urban core. Urban outskirts are defined in this report as medium-sized areas or neighbourhoods in the near context of an urban area, where high car dependency is present and a strong economical and functional connection to the city is observed, primarily through daily work commutes. The current academic literature and 15-minute city practices are mainly focused on the urban city centres, where the concept emerged, but new contributions and researchers are stating the need to look deeper into how the concept evolves in the context of the urban outskirts.
This report aims to answer the questions: what are the components or elements to consider when trying to achieve 15-minute neighbourhoods in the urban outskirts? How similar or different are these elements in an urban core vs urban outskirts?
To this end, we first frame our research scope in the terms that appear when describing the 15-minute neighbourhood concept, to set the common understanding of definitions along the rest of the project.
We therefore provide definitions on four terms (topics): 1) urban outskirts, 2) accessibility, 3) mobility services, 4) governance and 5) business models. Firstly, we define the spatial scope of DREAMS with the previous mentioned definition of outskirts as those mid-dense areas in the near proximity of city.
Secondly, we describe the term accessibility (and related terms walkability and proximity) and their relationships due to their common appearance when defining 15-minute neighbourhoods. For the case of our project, we understand proximity as physical distance between two points, while walkability is the extent to which the characteristics of the built environment and land use may be conducted of residents walking. And accessibility as the extent to which the land-use transport system enables (groups of) individuals or goods to reach activities or destinations by means of a (combination) of transport mode(s). Accessibility is the umbrella concept for 15-minute planning concepts where proximity-centred planning (planning for short distances) and active mobility (walk and cycle) becomes crucial. Thirdly, we describe the different mobility solutions or services that can support the development of sustainable and inclusive 15-minute neighbourhoods in the urban outskirts, including on-demand mobility, shared mobility (car-sharing and micromobility services), mobility hubs and flexible activity hubs. And finally, we define governance and business models which are also crucial to implement 15mN principals in different contexts.
With the research framed in the topics of interest, we searched and conduct a systematic literature review analysing 74 papers using the PRISMA methodology (48 with an urban focus and 26 mentioning or focusing on the outskirts). Our findings yield the need to adapt the concept of 15-minute city to different contexts considering public transport and mobility services as a key point to connect people in the outskirts to nearest urban cores and reduce car dependency. Therefore, we propose the following an adapted version of the 15mC for the outskirts (DREAMS 15-minute Neighbourhoods definition) as: The 15-minute neighbourhood (15mN) is a concept for the urban outskirts that advocates for reducing the need to use a private car in the urban outskirts, allowing its residents to access their essential amenities and thus, fulfilling daily needs through active mobility and local public transport, while also being well connected to other cores with regional public transport, shared mobility and micromobility services.